a question to chess.com staff: a real software bag or a primitive try to cheat?

Extremely unlikely that it's a bug. He blundered. Don't offer a draw unless you would have anyway.

EDIT: (Note that I am not a staff member )

Chances are near to certain that the guy blundered and is trying to protect himself. If there was indeed a bug, chess.com staff will resolve the issue; until that time, continue playing normally. Don't let such claims affect the way you play.

It was a result from a bug called blunder.

This type of bug happens rather often here on chess.com.

+1.

Hahaha Paul, that guy believes that he's too smart. After a silly blunder, he tried this ruse to trap U! Good that U didn't believe it! Just take his queen and win this game normally.

P.S. If someone really believes that there is a bug, he should submit himself a report to the support while continuing to play normally. That's clear to me.